1. Field of the Invention:
This invention relates to a video signal recording apparatus and more particularly to a video signal recording apparatus of the type in which, at the time of recording a video signal, a control signal is recorded simultaneously on a recording medium with the video signal.
2. Description of the Prior Art:
Recently, there has been an increase in video signal recording apparatus of the type having a connected or splice recording function which, in resuming a video signal recording operation after a temporary cessation of the recording operation on a recording medium such as magnetic tape, etc., permits a satisfactorily reproduced video signal even at a joint between the recorded video signal and a newly recorded video signal.
This function is especially common in video tape recorders (hereinafter called VTR's) of the type using a magnetic tape as the recording medium as a result of increased requirements for size reduction and picture taking. In the following description, VTR's of this type will be discussed as video signal recording apparatus:
The conventional VTR's perform the above stated splice recording opertion by various methods for synchronization of the existing record and a record being newly recorded, including: (1) a method of adjusting timing for stopping the magnetic tape and for allowing the tape to travel again; and (2) a method of recording after synchronization has been made with the existing recorded signal by rewinding the magnetic tape to some extent; etc. The method (1) above can be carried out with a simple structural arrangement. However, the method would become meaningless if the magnetic tape moves even a slight degree while the tape is in repose. It requires a high degree of mechanical precision. As for the method (2) above, the speed of a capstan drive system which drives the tape must be controlled and then the drive system must be further phase adjusted to the video signal and the control signal recorded on the tape (hereinafter the control signal will be called CTL) during the process of synchronization which is carried out after rewinding of the magnetic tape. The method (2) thus requires a long control time and thus necessitates rewinding the tape to a great extent. In accordance with the method (2), therefore, it is difficult to determine the timing for actually carrying out connected (or splice) recording. Another method has been attempted in which the phase adjustment of the CTL is quickly carried out after the speed of the drive system has been controlled. This method is, however, not desirable because the phase control loop of the apparatus becomes unstable.
In view of the above problems in the prior art, it is an object of the present invention to provide a video signal recording apparatus which permits connected (or splice) recording with only a short period of time required for synchronization. More specifically, the object is to provide a video signal recording apparatus which is capable of quickly carrying out the phase adjustment of the drive system, newly recording a video signal and recording a control signal on the recording medium.
It is another object of the invention to provide a video signal recording apparatus which permits connected or splice recording in a satisfactory manner even when the recording medium is rewound only slightly for that purpose.